Multimedia data files, or media files, are data structures that may include audio, video or other content stored as data in accordance with a container format. A container format is a file format that can contain various types of data, possible compressed a standardized and known manner. The container format allows a rendering device to identify, and if necessary, interleave, the different data types for proper rendering. Some container formats can contain only audio data, while other container formation can support audio, video, subtitles, chapters and metadata along with synchronization information needed to play back the various data streams together. For example, an audio file format is a container format for storing audio data. There are many audio-only container formats including known in the art including WAV, AIFF, FLAC, WMA, and MP3. In addition, there are now a number of container formats for use with combined audio, video and other content including AVI, MOV, MPEG-2 TS, MP4, ASF, and RealMedia to name but a few.
Media files accessible over a network are increasingly being used to deliver content to mass audiences. For example, one emerging way of periodically delivering content to consumers is through podcasting.
Podcasting is a method of publishing digital media, typically audio programs, via the Internet, allowing users to subscribe to a series of new files (e.g., MP3 audio files) as they become available over time. The word “podcasting” became popular in late 2004, largely due to automatic downloading of audio onto portable players or personal computers. Podcasting is distinct from other types of online media delivery because of its subscription model, which uses a “feed” (such as RSS, discussed below, and Atom) to monitor for and/or deliver a file. A feed in this context refers to an electronic means, such as a file containing a list of media files, that can be easily interpreted to identify new files in the list as the files are added over time. Thus, one is said to subscribe to a feed because as new files are added to the list, the subscriber is notified of the new file and, in some cases, the new file is automatically delivered to the subscriber.
Podcasting enables independent producers to create self-published, syndicated media, such as “radio shows,” and gives broadcast news, radio, and television programs a new distribution method. Listeners may subscribe to feeds using “podcatching” software (a type of aggregator), which periodically checks for and downloads new content automatically. Most podcatching software enables the user to copy podcasts to portable music players. Most digital audio player or computer with audio-playing software can play podcasts. From the earliest RSS-enclosure tests, feeds have been used to deliver video files as well as audio. By 2005 some aggregators and mobile devices could receive and play video, although the “podcast” name remains most associated with audio. Other names are sometimes used for casting other forms of media, such as blogcasting for text and vcasting or vodcasting for video. For the purposes of this application, podcast is used in its most general sense to refer to a feed of new files in any format (e.g., .MP3, .MPEG, .WAV, .JPG) and containing any content (e.g., text-based, audible, visual or some combination) that can be subscribed to. Also, for the purposes of this discussion an individual podcast feed may be alternately referred to as a series. Each distinct new file in a series or feed may be referred to as an individual episode of the series.
Podcasting is supported by underlying feed formats, of which RSS is but one example. RSS is a family of XML file formats for web syndication used by (among other things) news websites and weblogs. The abbreviation is alternately used to refer to the following recognized standards: Rich Site Summary (RSS 0.91); RDF Site Summary (RSS 0.9 and 1.0); and Really Simple Syndication (RSS 2.0).
Feed formats, such as the RSS formats, often allow the feed creator (referred to as the publisher) to include web content or summaries of web content together with links to the full versions of the content, and other meta-data. This information may be associated with different episodes of the feed, thus allowing an easy way to provide at least some summary information to the subscriber so that a subscriber does not have to render each episode to determine if it contains information of interest. This information may be delivered within an XML feed file, a webfeed, an RSS stream, or RSS channel.
The technology behind podcasting allows a client to subscribe to websites that have provided RSS feeds or feeds in other formats; these are typically sites that change or add content regularly. To use this technology the client needs some type of aggregation service or aggregator. The aggregator allows a client to subscribe to the podcasts that the client wants to monitor or to get updates (i.e. future media files in the feed) on. Unlike typical subscriptions to pulp-based newspapers and magazines, your RSS subscriptions are free, but they typically only provide a line or two of each article or post along with a link to the media file that contains the episode (e.g., the full text article, audio file or video file).
In addition to facilitating syndication, a feed allows a website's frequent readers to track updates on the site using an aggregator.
Feeds, including RSS feeds, are widely used by the weblog community to share the latest episodes' headlines or their full text, and even attached multimedia files. In mid 2000, use of RSS for podcasting text spread to many major news organizations, including Reuters, CNN and the BBC, until under various usage agreements, providers allow other websites to incorporate their “syndicated” headline or headline-and-short-summary feeds. Feeds are now used for many purposes, including marketing, bug-reports, or any other activity involving periodic updates or publications.
A program known as a feed reader or aggregator can check feeds, such as RSS-enabled webpages, on behalf of a user and display any updated articles that it finds. It is now common to find RSS feeds on major web sites, as well as many smaller ones. Client-side readers and aggregators are typically constructed as standalone programs or extensions to existing programs like web browsers. Such programs are available for various operating systems.
Podcasting has become a very popular and accepted media delivery paradigm. This success has caused the number and variety of podcasts available to clients to grow exponentially. Potential podcast consumers are now confronted with the problems of how to find podcasts, how to organize and manage their podcast subscriptions; and how to listen to episodes efficiently and easily. Podcast publishers are also confronted with problems including how to effectively market their podcasts, how to generate income from their podcasts, how to easily create and disseminate podcasts, how to support different feed formats and device needs, and how to manage bandwidth and storage costs.
Currently client-side readers must download some or all of an episode to the rendering device before the subscriber can begin to render the episode. This requires a substantial amount of bandwidth, storage space on the rendering device, and is a potential security risk to the rendering device.